Controlling device for electric motors.



NG DEVICE 'EDB ELEGTRIU MGTGRE PPLIGATIGJ FILM) NGV. le, i908,

JONTRGLLJ mHw-l apparatus is also applicableto the motors l}evices erElectric Motors, of which the following is a specification.

. deed in any situation where -comparatively `starting has to which thesaiddisadvantage'may be avoided.

the generator whichv then `immediately heanni sansa limitaron saisir,

geirrnnr ernten l ccnrscrnme marien ron caserme, morons.

Speccstien of Letters E'atcnt.H 'vPafbented Sept, i4., j fgqjg, I

npplcaticn'led November 16, 1598., Serial Kc. 462,837.

To al?, 'whom 'it 'may corriger-n.:

Be it known that I, Eimer HEXN'BIOH man Emperor, residing. atCologne-outliellhine, inthe Province of the Rhine, Kingdom of ldrussia,German. Empire, have invented certain ,new and useful Controlling Thisinvention.. relates to apparatus for the control of electric motorsespecially such as are used 1n hoists and cranes, although the employedin tramways'and railways, or insudden changes of output arenecessitated.

The object of the invention is to allowV the starting of the motorineither direction, or its stopping, or ot a rapid change of speedwithout-shock. i

if acrane motor is supplied from the cen'- tral station in the ordinarymanner, very great losses of energy occur whenever the crane is started,because naturally a much larger` current is required lfor starting thanorynormal running, While the voltage re` quired to propel vthat currentthrough the stationary or almost stationary armature of the motor, iscomparatively small. 'As a i'esultof this a very large part of thecxcessi-ve energy su .plied which is required on e wasted onresistances.- Various attempts have been made to. avoid thisdisadvantage oy the use of auxiliary dynamos, iiy Wheels 'andaccumulators. It, is also the object -of the 'present invention tcprovide a simple and effective means by According to the invention, thegenerator from whichcurren-t is supplied to the moor or motors to be reulated has a double field Winding, one Win ing being in series with thearmature and the other in shunt. This latter field alone can 'beregulated.

Prior to startingthe motor the generator is on open circuit andtherefore is unexcitcd. To start the motor this latter is connected togins to excite itself while sending a current. through the motorarmature. i By a diminution or' the resistance in the circuit of theshunt winding, the field of the generator can he strengthened and so itsvoltage and output ii'icreascd until the motor or motors hegin, withoutanyshoclc, to rotate. The speed 1 can then be further-regulated bythesame i. .'ieans. Cin-rsf, a subject of .the 'King of Prussia, Ger-Th'e invention is illustrated in the accomdcawings in ,which- 'Figure lshows .diagrammatically a generator connected to the contacts of aswitching device to which also the motors to be regulated are' joined.Fig. 2- shows in side elevation a switch Varm which is adapted to moveover the contacts shown in Fig. l so as t0 vary the connections in thedesired man- 1 ner.- l

In F ig. 11', a is the generator which may be driven by any suitableprimemotor, ag., an internal wmbustion motor lor anv electric motor.YThis generator a 'hase 'field winding a series with its armature, and ashunt a2 joined to one of its brushes and toonefoffthe end vcontacts c',of the switching arrangement c. In the switch there are a number ofcontacts c', c2, c3 6,1, 0,2., 03,. ,which-are joined in pairs as c10,1, 62h12, c of; .The connecting leads are also joined tothe parte of aresistance d of any suitable type'. The contacts clef' are arranged in.a circular are .as .shownfwith a space infsthe middle.- Concentric.with them are metaliicircular segments. e and f, and bet\veen,-.;tl1'ese ents are arranged other vsegments of which the outer vis dividedinto three portions g, JL, lo, and the inner into two portions Z, m.'The segment 'g is con-v nected' directly with the segment m and thesegment Z with the segment lc. The segments I1, and la arejoined througharesistance .connectedas shown to a termina-lof the l The motors b haveeach one terminal generator a, and' their. other' terminals to aconductor joined to the segment f. The remaining terminal ,of thearmature of thel machine a is joined to the segment e, and the elds ofthe motors b are connected across conductors joined respectively to thesegments m and lc.

From Fig. 2 it Will be seen that. the switch arm p, Whichis providedwith a han dle q by which it may be operated, has two sets of contacts.'The outer set comprises three brushes 7", s, ,-connected together andadapted to bear respectively on the ring of contacts c1, 0,1 etc. on;the segment e and on the segments h, la. The `second set of contactscomprises'two brushes u., `vv. connected together and adapted Yto 'nearrespectiyely on the segments Z, mand f.

aco

'15 arm successively moves over the contacts When the switch arm in the-position indicated by the line 1 t e motors b are not connected to thegenerator a. If'the switch. arm is moved t'o the position l the motorfields are immediately connected in seriesv with their armatures and arejoined to the terminals of the generator a, the resistance n however,being interposed in the circuit. If

the switch arm is moved farther tothe righi;v to the position 2, theresistance'n i out out of circuit. Fu rther movement of thel switch`arni brings the brush 1 on to the contact ,f'" when the circuit ofthe-shunt winding a2 of the generator a is completed through the wholeof 'the resistance d. As the 'switch c1, 0,4, 0,3 ete. the parts of thisresistance d arel cut out until in the position 3*l the winding a2 issimply in-shunt with the armature of'the machine d. Movement of the'switch arm p inthe opposite direction brings about a similar series ofevents. In the position 2 the'motors b are joined to the generatore butinthis case there is no -resistance n interposed. Moreover owing totheconnections of the segments g, m, l, lc, the current now traverses `thefields of the machines inthe opposite direction to that taken-before,so'that the motors will be 'n to run Aso in the opposite direction. Furter movement of the switch arm p to the left completes the shunt circuita2 through the resistance (Z, and then gradually removes the resistancefrom the circuit until in the position 3 the shunt winding isagaindirectly connected to the brushes of the machine.

.It .will be seen that this a paratus pro-' vides for the method of reation first set out above, namely, whenthe moton to be regulated is tobe started, it is first joined to the terminals of the generator.Current then begins to Howland the generator to exciteitse f by meansofits series coil. -When the shunt circuit is completed the field isfurther increased andas-resistance is cut out the 'current through themotor attains such al .value that it begins to rotate, but withoutany'fsudden start.- Aterrthis speed variaings, the resistancesand-said'switching device, whereby thel iieldand 'amature cir-l cuits ofthe-generator may be `closedthrmgh lthe switch and the resistancesinserted-'into and removedvfromthe circuit ofthejsecond field winding.

name to this .specification in the presence of twosubscribing-witnesses. l

` ERNST HEINRICH GEIsT.-

iVitnesses: A

Louis VANDORN,

H. S'rETzER.

tio'n may be eieeted simply byvar ing the tions between the generatorand motor wind` '.In testimony .whereof I. have signed g

